ON THE SPATIAL AND TEMPORAL BEHAVIOR IN LINEAR THERMOELASTICITY OF MATERIALS WITH VOIDS

The present article studies the spatial and temporal behavior of the solutions to the initial boundary value problems associated with the linear theory of thermoelastic materials with voids. The spatial behavior is described by spatial estimates of Saint-Venant type (for bounded bodies) and Phragmén-Lindelöf type (for unbounded bodies) with time-dependent and time-independent rates. Some appropriate time-weighted integral measures are used. The temporal behavior is studied using the Cesaro means of various parts of the total energy. The relations describing the asymptotic behavior of the Cesaro means are established.     

EFFECT OF POLLUTANT OSCILLATIONS ON OIL SPREADING ON THE SEA

Analytical solutions for oil spreading on the sea are deduced when the pollutant source fluctuates with time for a simple rectangular geometry. Both asymmetrical and symmetrical solutions in the direction perpendicular to the uniform tidal stream are derived. The asymmetrical solution, though ad hoc, sheds light on the necessary adjustment to the simpler symmetric problem. Only a micro computer is necessary to simulate these solutions. © 1997 by John Wiley & Sons, Ltd.     

APPLICATION OF AN ALTERNATING METHOD TO THE THERMOELASTIC PROBLEMS WITH MULTIPLE CIRCULAR HOLES IN AN INFINITE DOMAIN

This paper presents a new efficient procedure to analyze the thermoelastic problems with multiple circular holes in two-dimensional infinite domain using an alternating method. To achieve this purpose, the analytical solutions including the temperature and associated thermal stress for the arbitrary heat flux across the single circular hole boundary in an infinite domain are first derived. Both the temperature and thermal stress fields in the thermal problems are simultaneously solved by these analytical solutions with the successive iterative superposition process. Compared with the solution of the conventional finite-element technique, the present method has been more accurate and has more advantages. Effects of the distributions and sizes of the holes on the stress concentration in the thermal problems also are evaluated in detail herein.     

EFFICIENT REFORMULATION OF THE THERMOELASTIC HIGHER-ORDER THEORY FOR FUNCTIONALLY GRADED MATERIALS

The majority of techniques employed in the analysis of functionally graded materials (FGMs) use the so-called uncoupled approach, based on homogenized material property variations, which ignores the effect of local microstructural interaction. The higher-order theory for FGMs (HOTFGM) is a coupled approach that explicitly takes the effect of microstructural gradation and, thus, the local interaction of the spatially variable inclusion phase(s), into account. Despite its demonstrated utility, however, the original formulation of HOTFGM is computationally intensive. Herein, an efficient reformulation of HOTFGM is presented based on the local/global conductivity and stiffness matrix formulations. In this approach, surface-averaged quantities are the primary variables which replace volume-averaged quantities employed in the original formulation. The reformulation eliminates redundant continuity equations and, therefore, decreases the size of the overall systems of equations for the thermal and mechanical problem by approximately 60%, facilitating modeling of realistic microstructures. Explicit expressions for the elements of the local conductivity and stiffness matrices, which relate the surface average heat flux/traction quantities to the corresponding surface average temperatures/displacements, facilitate the theory's implementation, as well as comparison with the finite-element approach. The presented results illustrate the efficiency of the reformulation and its advantages in analyzing FGMs.     

ON THE PROPAGATION OF THE THERMAL WAVES IN MATERIALS WITH MEMORY

The propagation of one-dimensional acceleration waves in linear thermoelastic materials with thermal memory is analyzed. It is shown that two types of waves may exist, and the properties of velocities and attenuation of these waves are examined. The obtained results are compared with the data of the previous works     

FUNDAMENTAL SOLUTIONS OF THE EQUATIONS OF THE THEORY OF THERMOELASTICITY WITH MICROTEMPERATURES

By means of elementary functions, the fundamental solutions of the equations of the equlibrium and steady oscillations of the theory of thermoelasticity with microtemperatures are constructed, and basic properties are established.     

有机相变材料储能的研究和进展

回顾了近十年有机物应用于能量储存的研究工作,这些研究工作被分为有机物相变储能实际应用研究、有机物相变参数及相变循环热稳定性研究、有机物相变过程的相变传热及传热强化研究3个方面。分析讨论了有机物用于储能研究今后需要重点解决的问题。     

NOTE ON THE SOLUTION OF THE EQUATIONS CONTROLLING STABILITY OF NONLINEAR THERMOELASTIC WAVES IN A SPINNING DISK

A general solution to the system of coupled differential equations with periodic coefficients, established in [1] and determining the stability of a spinning heated disk, is given.     

电沉积制备中络合剂对光伏材料CdS的影响

利用电沉积（Electrodeposition)方法来制备六方相的CdS薄膜。实验指出从0．04mol/L Na2S2O3,0.04mol/L,CdSO4和0.04mol/L柠檬酸钠组成的溶液中，在pH值为5．4，温度为60℃的条件下，在ITO玻璃上电沉积得到CdS的前驱体。在300℃氮气氛下中热处理1h后，经X射线衍射（XRD）分析表明薄膜是呈六方相的CdS，且几乎沿（002）方向定向生长。扫描电镜（SEM）表明CdS晶粒为亚微米尺寸。研究表明，利用这种方法，可以得到结晶良好的六方相CdS薄膜。     

太阳能-地热道路融雪系统路面传热特性的数值研究

初步建立了道路融雪系统的路面传热模型,并基于典型年逐时气象数据与复合边界条件,进行了稳态传热数值模拟,分析了不同埋管深度和加热温度对道路融雪性能的影响,得到了最大和待融热负荷与降雪量、环境温度、相对湿度以及风速等因素之间的关系,可为工程设计应用提供必要的参考依据。     

光电型总日射表性能的初步研究

对光电型总日射表与ＰＳＰ型总日射表进行了对比测试。在带有圆柱形余弦修正器时光电型总日射表的灵敏度尚佳。在太阳高度角小型３５°、没有温度补偿或将传感器与二次仪表做成一体时其误差较大     

TIM复合墙体的动态传热研究

分析了带有透明绝材料的建筑墙体的传热过程，给出了简单、合理的计算模型，并以实例说明这种本的节能效果。     

组合式相变材料组分配比与储热性能研究

采用焓法对组合式相变材料(PCM)储热系统的相变过程进行了数值计算,分析了组合式相变材料中各个PCM组分质量分数的变化对系统储热性能的影响。结果表明,对于组合式相变材料储热系统,存在着最优组分配比,使得系统的储热性能达到最佳。     

空间电荷区和晶界复合对多晶太阳电池基区少数载流子寿命的影响

该文采用多晶硅太阳电池模型，通过引入空间电荷区复合速度来研究空间电荷区复合对少子寿命的影响，从计算结果中发现当复合速率大于10^5cm／s时，空间电荷区的复合影响不可忽略，必须对所测得的寿命值进行修正。     

管簇结构腔体式吸收器热效率所受边界条件的影响

分析了槽形势物镜聚光集热器中管族结构腔体式吸收器的热物理特征，依据其热阻网络、太阳能一般性控制方程和计算框图对其热效率在自动跟踪条件下所受边界条件影响作了数值分析。     

秸秆冷态压缩成型微观结构变化的实验研究

采用扫描电子显微镜,在不同压缩成型条件下对3种秸秆冷态压缩成型前后微观结构变化进行实验研究,通过秸秆原料和颗粒燃料在纵横截面微观结构变化的对比分析,得出秸秆冷态压缩成型的微观结合方式,总结出压缩成型条件对秸秆微观结构的影响规律。实验结果表明:当压缩速度取40mm/min、秸秆原料为玉米秸秆时,冷态压缩成型效果最佳。     

ON THE REDUCTION OF CONSTANTS IN PLANAR COSSERAT ELASTICITY WITH EIGENSTRAINS AND EIGENCURVATURES

We study the reduced parameter dependence in linear plane Cosserat elasticity with eigenstrains and eigencurvatures. The focus is on singly connected inhomogeneous materials. We find conditions on the eigenstrains and eigencurvatures for the planar stress field to be invariant under a shift in area Cosserat compliances. The analysis can be extended to multiply connected inhomogeneous or multiphase materials. The special case is linear planar uncoupled micropolar thermoelasticity where eigenstrains represent the product of thermal expansion and temperature change.     

碳纳米管超大容量电容器在光伏系统中的应用

该文以太阳电池为能源和以碳纳米管超大容量电容器为储能元件组成的电源模型系统作为研究对象，考察这类系统的运行特征。并与太阳电池和铅酸蓄电池组成的模型系统进行了比较，分析了差异的形态原因及其在储能应用中的影响。     

EFFECT OF THERMAL RESIDUAL STRESS ON THE INTERLAMINAR CRACK EXTENSION BEHAVIOR IN CROSS-PLY LAMINATES DUE TO TRANSVERSE LOADING

The effect of thermal residual stress on the two-dimensional interlaminar crack extension behavior in a cross-ply laminate subjected to transverse loading is estimated. Attention is focused on the contribution of thermal residual stress to the local energy release rate along the interlaminar crack front. Computational simulations are carried out on the basis of constant critical energy release rates in order to examine implicitly how the two-dimensional size and shape would be changed by the presence of thermal residual stress. A considerably large amount of energy is found to be supplied for the interlaminar crack extension by thermal residual stress, while little influence is perceived with respect to the apparent extension behavior including the shape of the interlaminar crack.     

表面光电压法测量a—Si：H少子扩散长度的进一步研究

建立用ＳＰＶ法测量ａ－Ｓｉ：Ｈ薄膜少子扩散长度Ｌｐ的新的数学模型，推导出可供具有有任意输入端口的锁相放大器所使用的测量Ｌｐ的数学表达式，为改进测试过程和提高准确度创造了条件。对合理选择偏置光强度做了较细致的分析，并从实验技术上提出确定偏置光强度的选择准则，给出了测试结果；也分析了不同强度偏置光和不同金属与ａ－Ｓｉ：Ｈ肖特基结对测量结果的影响。